Combined predistorter and feedforward corrector apparatus suitable for use in a transmitter

Abstract

In accordance with the present disclosure, there is provided a predistorter combined with a feedforward corrector that addresses power dissipation of the feedforward error path while maintaining a sufficiently simple digital predistortion model so as to further minimize power dissipation without sacrificing linearity.

What is claimed is: 
     
         1 . A combined predistorter and feedforward corrector apparatus suitable for use in a transmitter for improving at least one of power dissipation and linearity in the transmitter, comprising:
 a predistorter, for receiving an input signal, and for providing a predistorted signal by performing as much linearization as necessary to predistort the input signal within the predetermined bounds of linearizer efficiency and correction required by the transmitter;   a power amplifier, for receiving the predistorted signal, and for providing an amplified predistorted signal by amplifying the predistorted signal, connected to said predistorter;   a feedforward corrector, for receiving the input signal, and for providing a correction signal by correcting any remaining distortion that the power amplifier produces that the predistorter did not correct; and   a summator, for receiving the amplified predistorted signal and the correction signal, and for providing an output signal by summing the amplified predistorted signal and the correction signal, connected to said feedforward corrector, and connected to said power amplifier.   
     
     
         2 . The combined predistorter and feedforward corrector apparatus suitable for use in a transmitter as recited in  claim 1 , further comprising:
 an actuator, for receiving the input signal and for providing at least one of a predistorted input signal and a corrected input signal.   
     
     
         3 . The combined predistorter and feedforward corrector apparatus suitable for use in a transmitter as recited in  claim 1 , further comprising:
 an adjustment block, for receiving an adjustment input signal comprising at least one of the input signal and an input adjusted amplified predistorted signal, and for providing a respective one of an adjusted input signal and an unamplified correction signal respectively, by adjusting at least one of gain, phase, and delay of the adjustment input signal.   
     
     
         4 . The combined predistorter and feedforward corrector apparatus suitable for use in a transmitter as recited in  claim 1 , further comprising:
 an adaptor, for receiving at least one of the input signal, the output signal, the amplified predistorted signal, and an input adjusted amplified predistorted signal, and for providing an adapted signal which is adapted to a change in the electronics environment to be used by one of an actuator and an adjustment block.   
     
     
         5 . The combined predistorter and feedforward corrector apparatus suitable for use in a transmitter as recited in  claim 1 , further comprising:
 an error amplifier, for receiving an unamplified error signal including at least one of an unamplified correction signal, an adjusted input signal, and a corrected input signal, and for providing the correction signal by amplifying the unamplified error signal.   
     
     
         6 . The combined predistorter and feedforward corrector apparatus suitable for use in a transmitter as recited in  claim 1 , further comprising:
 a second summator, for receiving the amplified predistorted signal and an adjusted input signal, and for providing an input adjusted amplified predistorted signal by summing the amplified predistorted signal and the adjusted input signal, connected to said adjustment block, and connected to said power amplifier.   
     
     
         7 . The combined predistorter and feedforward corrector apparatus suitable for use in a transmitter as recited in  claim 1 , further comprising:
 an upconverter, for receiving an upconverter input signal comprising at least one of the predistorted input signal, an adjusted input signal, and a corrected input signal, and for upconverting the upconverter input signal.   
     
     
         8 . The combined predistorter and feedforward corrector apparatus suitable for use in a transmitter as recited in  claim 1 , further comprising:
 a downconverter, for receiving a downconverter input signal comprising at least one of the amplified predistorted signal, the output signal, and an input adjusted amplified predistorted signal, and for downconverting the downconverter input signal.   
     
     
         9 . The combined predistorter and feedforward corrector apparatus suitable for use in a transmitter as recited in  claim 1 , further comprising:
 a controller, for sensing at least one of the output signal, and the amplified predistorted signal, the input adjusted amplified predistorted signal, and for controlling at least one adaptor, connected to said predistorter, and connected to said feedforward corrector.   
     
     
         10 . A method of controlling the apparatus recited in  claim 1 , the method comprising the acts of:
 sensing signals, including at least one of the output signal, and the amplified predistorted signal;   determining if predistorter linearization is sufficient enough to predistort the input signal within the predetermined bounds of linearizer efficiency and correction required by the transmitter   if predistorter linearization is determined to be sufficient enough, then decreasing the amount of feedforward correction in the feedforward corrector; and   if predistorter linearization is determined not to be sufficient enough, then increasing the amount of feedforward correction in the feedforward corrector.   
     
     
         11 . The method as recited in  claim 10 , wherein the act of decreasing the amount of feedforward correction in the feedforward corrector comprises the act of disabling the feedforward corrector. 
     
     
         12 . The method as recited in  claim 10 , wherein the act of increasing the amount of feedforward correction in the feedforward corrector comprises the act of enabling the feedforward corrector.